JPS6162572A - Corrosion-resistant coating compound composition - Google Patents

Abstract

PURPOSE:The titled composition having improved long-term stability and contamination resistance, comprising a chlorinated polyethylene having a specific chlorine content and specified molecular weight as a main component of resin vehicle. CONSTITUTION:The aimed composition comprising a chlorinated polyethylene having 45-60wt% chlorine content and 3,000-20,000, preferably 6,000-7,000 number-average molecular weight as a main component of resin vehicle (a solid content weight ratio of preferably 30-100% in resin).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anticorrosive coating composition, and more particularly to an anticorrosive coating composition containing a specific chlorinated polyethylene as a main component of a resin vehicle.

Chlorinated rubber paints made of chlorinated polyolefin resins obtained by chlorinating polyolefins such as polyethylene, polypropylene, and polyisoprene have been proposed as anticorrosive paints for steel structures and the like. However, the chlorine content of the chlorinated polyolefin resins used in these paints is usually 60% by weight or more, and liquid plasticizers such as phthalate esters and chlorinated paraffins are included as essential components, making the paint film waterproof. Although they have excellent properties such as corrosion resistance, adhesion, and chemical resistance, it has been pointed out that such anticorrosive coatings have problems with long-term stability and have poor stain resistance.

This is because polyolefin resin with a high chlorine content has poor internal flexibility, so it is difficult to form a coating without adding a liquid plasticizer, and the liquid plasticizer separates from the coating over time, causing the coating to become brittle. This was due to the fact that the coating film lacks long-term stability, and the liquid plasticizer has a tendency to extremely lower the softening point and glass dislocation point of the coating film, making it easy to stain.

In Japanese Patent Publication No. 58-20990, an attempt was made to improve weather resistance and plasticizing ability by using a chlorinated polymer and a chlorinated vinyl acetate copolymer, and in another study, alkyd, acrylic Attempts have been made to reduce the amount of chlorinated polyolefin and liquid plasticizer by using polymer compounds such as It is also recognized that the advantages of rubber are reduced.

On the other hand, polyolefin with a 14X conversion rate of 45 to 60%
The reality is that there is no commercially available product and its properties have not been elucidated.

Therefore, the object of the present invention is to provide an anticorrosive coating composition containing a chlorinated polyolefin as a resin vehicle, which has long-term stability,
The object of the present invention is to provide a composition that does not have drawbacks such as stain resistance.

The inventors found 13! As a result of synthesizing various types of polyethylene with different elemental contents and various studies on their properties, the number average molecular weight of polyethylene resin was found to be 3,000 to 20,000.
, preferably 6000 to 7000, and the chlorine content is 45 to 7000.
It was discovered that if chlorinated polyethylene containing 1 m% of 6C is selectively used, an excellent anticorrosive coating composition can be obtained without using a liquid plasticizer in combination, and the present invention was completed.

That is, according to the present invention, the chlorine content is 45-60% by weight and the number average molecular weight is 3000-2000C1)j! There is provided an anticorrosive coating composition containing iff-formed polyethylene as a main component of a resin vehicle, preferably in a proportion of 30 to 100% by solid weight in the resin.

The first discovery of the present invention is that even if highly chlorinated polyethylene with a chlorine content exceeding 60% by weight is not used, the anticorrosive effect can be sufficiently exhibited and the objects of the present invention can be achieved. On the contrary, if the chlorine content exceeds 60mff1%, a liquid plasticizer will be required due to deterioration of internal flexibility. On the other hand, if the chlorine content is less than 45%, the softening point is too low, resulting in poor stain resistance and poor compatibility with other resins such as alkyds and acrylic resins, making it unusable.

The molecular weight of the chlorinated polyethylene resin is also important; low molecular weight ones with a number average molecular weight of less than 3,000 will not cure the paint sufficiently, and will not be suitable for practical use in terms of water resistance, weather resistance, and plasticity of the paint film. On the other hand, it was also found that when it exceeds 2000, the coating workability is poor and the compatibility with other resins is extremely poor.

Chlorination of polyethylene can be easily carried out according to a conventional method by dissolving polyethylene in a suitable solvent such as carbon tetrachloride, introducing chlorine gas and causing a reaction.
Furthermore, control of the chlorine content is relatively easy. After chlorination, if the solvent is converted using a paint solvent, it can be used as is as a varnish.

The inventors have also found that polyethylene with a number average molecular weight of 6000-7000 and a degree of chlorination of 50-53% is a particularly useful and preferred material.

The present invention provides a coating composition containing the above-mentioned chlorinated polyethylene as a main component of the resin vehicle, and does not require a liquid plasticizer, but improves coating film performance, especially stability over time.
In terms of stain resistance, a liquid plasticizer may be added as long as it does not have a practical negative effect. Furthermore, since the chlorinated polyolefin of the present invention is characterized by excellent compatibility with other resins, if desired, alkyd, epoxy-modified alkyd, alkyd-modified acrylic, acrylic, ketone, phenol, xylene, coumaron, indene, modified phenol, etc. Petroleum resin etc. can be blended.

The chlorinated polyethylene of the present invention preferably contains in the resin component:
It accounts for 30 to 100% in terms of solid molecule fiffi ratio.

In addition, coloring pigments such as titanium oxide, extender pigments such as clay and talc, paint solvents, and other additives can be freely combined.
It can be used as an anticorrosion paint for ships, plants, bridges, etc.

The present invention will be explained below with reference to Examples.

Production example 1 Chlorinated polyethylene varnish (co)! ll
Polyethylene with a molecular weight of 3000 is chlorinated in a CCl4 solution to make the amount of chlorine 40%, and this is converted to Kijiroru solvent, with a non-volatile content of 50% and a viscosity of 1.5 poise/2.
A 5°C varnish was obtained.

Production Example 2 Production of Chlorinated Polyethylene Varnish (2) Polyethylene with a molecular weight of 3000 was chlorinated in a CCl4 solution to make the amount of chlorine 48%, and this was added to Kijirol solvent to give a non-volatile content of 50% and a viscosity of 2.0 poise/2.
A varnish at 5°C was obtained.

Production Example 3 Production of Chlorinated Polyethylene Varnish (3) Polyethylene with a molecular weight of 3000 was chlorinated in a CC14 solution to make the chlorine content 53%, and this was converted to a Kijiroru solvent, with a non-volatile content of 50% and a viscosity of 15°Q poise/
A 25°C varnish was obtained.

Production Example 4 Production of Chlorinated Polyethylene Varnish (4) Polyethylene with a molecular weight of 10,000 m was chlorinated in a CC1a solution to give a chlorine content of 58%, which was then converted to a Kijiroru solvent, with a non-volatile content of 30% and a viscosity of 12Q poise/
A 25°C varnish was obtained.

Examples 1 to 4 and Comparative Example 1 The chlorinated polyethylene varnishes obtained in Production Examples 1 to 4 and Super Chron 510 (manufactured by Chongyang Kokusaku Pulp Co., Ltd., chlorination degree 6)
8% polyethylene varnish) was used in the following formulation, and the paint composition was 111! IA-E was obtained.

The following performance tests were conducted on each of the above coating compositions.

Contaminated carbon method Each sample was applied once with a brush to a tin plate, and the dry film thickness was 40 μm.
After heating this coating film at 80°C for 3 hours, carbon pigment was sprinkled on the coated surface in a 20°C atmosphere, and the coating was heated to a predetermined temperature (20°C,
After heating at 30°C, 40°C, 50°C, 60°C for 30 minutes, wash with water and check the degree of carbon removal.

×...Significant carbon adhesion O...Each sample was applied twice with a brush to a natural Bacro sandblasted steel plate that can be completely removed, and the dry film thickness was 80μ. , L1 color difference was measured. If the L value is less than 90, stains will be recognized, and if the L value is around 80, the stains will be significant.

40"C salt water immersion evaluation Each sample was applied twice with a brush to a sandblasted steel plate to give a dry film thickness of 80μ. After immersion, JIS-54006, 1 was applied.
Check the adhesion in Section 5.

Peeling indicates cohesive failure.

Flexibility According to JIS K 5400 6.16.

Dry film thickness 30μ

Claims (2)

[Claims] (1) Chlorine content 45-60% by weight, number average molecular weight 30
An anticorrosive coating composition containing 00 to 20,000 chlorinated polyethylene as a main component of a resin vehicle. (2) Chlorinated polyethylene is added to the resin at a solid content weight ratio of 3
The composition according to claim 1, containing 0 to 100%.